Eukaryotes

we have around 100K different molecules in our cells.

we have ~63 trillion cells

we have ~30K protiens

so how do we explain unified functionality?

note that we did a big drawing of a euk cell here with lots of labeling of parts. Exact positions were not the emphasis so much as the list of organelles and some characteristics; there is more on each organelle later in the lecture(s)

The important labels on a Eukaryotic cell

Nuclear pores for RNA to get out

Vacuoles

90% of plant cells is the vacuole; that's how you know it is a plant cell!

Peroxisomes

do oxidations to get rid of toxic things

stick oxygens on things to make them sticky

Gap junctions (where two cells can hook together and make a membrane bridge to each others' cytoplasm

Nucleus

Holds DNA which is 6 x10^12 grams but 2 meters long and 20 angstrums thick

if DNA were as thick as a shoestring, the length would be 50k miles long!

controls open and closing / folding and unfolding of DNA

pores selectively allow RNA out

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Endoplasmic Reticulum

Rough Endoplasmic Reticulum

has ribosomes on its surface

the inside is called the lumen (which means "inside of sac")

proteins made on the RER can go into lumen or into RER membrane

if they go on the membrane then they can be spread to the golgi (via vesicle pinch off, travel and fusing) and from the golgi to anywhere else in the cell

Smooth Endoplasmic Reticulum

does lots of sterol biosynthesis

Golgi Apparatus

named after Carnello Golgi who won a nobel prize for his finding the Golgi

looks like a stack of lobes with 3 regions: Cis, Medial and Trans

the golgi is a two way street.

Lysosome

Single membrane

sometimes called the suicide sac because it can be signaled to burst and all the enzymes inside destroy everything in the cell effectively ending its lifespan.

some 40 hydrolytic (hydro = water, lytic = cut; so meaning they cut by adding water) enzymes are used in the lysosome

Condensation is the opposite of hydrolysis -- it uses the removal of water to put two things together

Mitochondria

power house of the cell; ATP is made here via oxidative phosphorylation.

size is about 2 microns (about the same size as a bacteria; probably because it once was an independent bacteria)

semi autonomous. it is a self replicating organelle

they grow to maturity and die separately from the cell cycle

only makes about 9 proteins (all the rest they would have made have been exported to the organisms' genome to be made by the ER)

~one-fifth of the cell can be mitochondria (they are numerous and pretty big)

levels of mitochondria vary between the many types of cells: highest capacity for mitochondria is found in insect flight muscles (because they need lots of energy really fast); they have as many as 2k mitochondria / cell.

the liver as ~1k mitochondria / cell because that's where everything is made

where more energy is needed, you'll find more mitochondria

Important vocab to be able to label on a picture of a mitochondria:

Inter-membrane space: a major area of activity

Matrix: a major area of activity (where Kreb's Cycle (except succinate dehydrogenase which is in cristae), gluconeogenesis, urea cycle and oxidation occur)

Outer-membrane: boring

Inner-mitochondrial membrane: where electron transport chain, oxidative phosphorylation, and trans-membrane transport take place

Cristae: the many small branches that increase surface area of the inner membrane.